No specular map as it isn't compatible with the current lighting model. Roughness/metalness should be used instead. A fully custom material/lighting models are possible but that will be up to the individual developer to implement, and I might extend the default material library as the time goes on.

"There is no option to rotate around selected, but it is planned." excellent!

Nodes;Material nodes; https://docs.blender.org/manual/en/dev/render/blender_render/materials/nodes/introduction.htmlKismet nodes; https://docs.unrealengine.com/udk/Three/KismetUserGuide.htmlThese are examples of nodes used in different apps.They are an easy way of producing different results for materials, animations, HUDs, UIs etc.Nodes are used in UE2, UE4, Unity et al.